An antisense oligonucleotide is a single stranded nucleotide that hybridizes with a complementary nucleic acid (e.g., an mRNA) in a sequence-specific manner. The formation of a heteroduplex between the antisense oligonucleotide and mRNA interferes with expression of the mRNA in a cell. This interference is thought to occur by one or more of the following mechanisms: the heteroduplex triggers RNase H activity, leading to degradation of the complex; the heteroduplex prevents the RNAs from being translated into proteins by steric hindrance, or the heteroduplex interferes with mRNA maturation by inhibiting splicing and/or destabilizing mRNA. See, e.g., Chan et al., Clin. Exp. Pharm. Phys., 33:533-540, 2006.